Slack adjuster



Jan. 20, 1959 .1. A.BuvELoT SLACK ADJUSTER Filed Feb. 2'?, 1956 BY/mxlw United States Patentl O F'ice Thisinvention relates to slackadjustersand-morefpathvv ticularly -to ali slack@ adjuster arrangementl adapted? for use'withrailway car brakes.

The invention comprehends a.slacksadjustingdevice\v comprisingiare'frame formed: on the endfofa:tiezrodi-or.l other element ofv the brake linkage, afunitary .brake lever fulcrum block assembly slidably disposed. Within the z frame, and a manually operated screw/mechanism*` inter-- connecting the block and frame and 'operable to"vary';the' position of the block vin the frame in-order totakeup slackf; inv the brake linkage.

Althoughslack adjusters of this general typev havev4 beenheretofore employed in brake-riggings, mostof the.vr conventional arrangements employa brake -`1everfulcrumr block-assembly including a plurality?. of fpartslpinnedfv or. bolteditogether. Because of'the tremendous stresses-'stoE whi'chrthese fulcrum'block assemblies are subjectedgtthe;k advantages of a unitary assembly are obvious-f Howevenf. the problem of assembling sucha device has prohibited, until now, the `design ofa slackadjuster'witha unitary fulcrum block assembly.

Itis therefore a primary object of thist-inventionito. provide an improved slack adjuster having a unitary",full crum block assembly.

Another object of 'the-inventionV isfthe provision of a slackil'adjusterthaving Va unitary fulcrum-fblock assembly in interlocking sliding engagement with the frame.

A further object of the invention is the provision of a slack adjuster comprising a frame having a fulcrum block movably retained therein by a pair of auxiliary plates.

A more specific object of the invention is the provision of a slack adjuster comprising a frame having a movable fulcrum block retained therein by means of a pair of retaining plates rigidly secured to the block to provide a unitary fulcrum block assembly slidably engageable with the frame.

These and other objects of the invention will be apparent from an examination of the following description and drawings, wherein:

Figure 1 is a fragmentary top plan view of a slack adjusting device embodying features of my invention,

Figure 2 is a fragmentary side elevational view of the structure illustrated in Figure l, and

Figure 3 is an end elevation-al View of the structure illustrated in Figure l, with portions of the frame shown in vertical section.

Referring now to the drawing for a better understanding of the invention, it will be seen that atie rod indicated generally at 10 is disclosed as having formed at one end thereof a frame 12 comprising spaced longitudinally extending arms 14 and 16 joined at their opposite ends by a wall 18 to present a closed slot 20 therebetween.

Disposed within the slot 20 for sliding movement longitudinally of the frame is a fulcrum block assembly indicated generally at 22 adapted to fulcrum a brake or truck lever 24. The right hand extremity (not shown) of the tie rod is normally connected to another lever or link (not shown) of the 'brake rigging.

The',fulcrumfblockassembly, asfbest seen vin lFigure'f;

.v includes ya pair of substantially:r L-.shaped retainngi plates 26;?eachwof :which comprises asubstantially flat'sidev element lt28-and 'faf-substantiallyflat end` element 30'1preferably formed integrally with the side element and extending outwardly therefrom and normally thereto.

The -platesf26 arevpositionedfat oppositesides of'fslot 20with `the'outersurfaces 29. and 31 of the'side'and end' elements-'.28 andz30; repsectively,.disposedi in slidngfexi'y gagenient Awith theinne'rI and upper surfaces 33 and 35;v respectively,f;of thef arms '14' and ;16'.

The-fulcrum` blockf 38` comprises'fa pair"l of 'i substantial` Y ly 'atfsp'aced side; walls r40 interconnectedvat one 1 end 'by'. a ht1b- 42zand havingwiebs `or flan-ges'44fpreferablyformed'f7 integrally 1: therewith-iv and extending: outwardly f from-l the.-y

lowerredges :thereof-.1v

Thefside wams 4e or the fulrum` block: andinas-mlelem'ents-i-ZS: of 1 the retaining. plates f are: provided withlongitudinally sand'z'verticallyextending slots 4S and 47,

respectively;yvliichfoverlapy adjacent their closed endsand whichiserve'fto ret-ain-'invpositiona fulcrumV pin 48'; aboutwhich the 'flever..24 f' is pivoting` or l fulcrumed.-

the f fulcrum blocktassembly'.andV the frames` To`v vary" 'theapositi'onf of the t fulcrum block assembly t withinfslotefZr-of the frame; a'fmanually 'operatedfsc'rew y indicated l'gener-allyf lat f50'is employedA to; connect .the aas@ desired manner as by cotter 59.

To assemble the device, the retaining plates 26 are positioned in opposite sides of the slet 20 in engagement with respective arms 14 and 16 of the frame as above described.

A brake lever 24 is fulcrumed to the fulcrum block by inserting pin 48 into the open end of fulcrum block slots 45. The fulcrum block is then inserted between the retaining plates 26 from the bottom as seen in Figure 3 with the ends of the pin 48 being received in the open ends ot the retaining slots 47. Once positioned, the fulcrum block is rigidly secured to the plates by welds 25 to form a unitary fulcrum block assembly. The body 54 of the screw 50 is then threaded through frame wall aperture 49 Iand inserted in fulcrum block hub aperture 57 and nonrotatably secured to the fulcrum block hub by the cotter 59. In order to prevent the accidental withdrawal of the screw from the frame, a key 61 may be inserted through the screw at a point adjacent the fulcrum block hub.

In describing the operation of the assembly, it will be understood that adjustment of a brake shoe must occur by moving the brake shoe fulcrum point towards the wheel. In the disclosed invention, this movement occurs when the pin 48 moves 'away from wall 13, or to the right as seen in Figures 1 and 2. For purposes of illustration, it will be assumed that screw 50 is retracted from the slot 20 but is in its assembled position with respect to the fulcrum block. When it is desired to adjust the brake shoe, cotter 59 is withdrawn from the assembly. Screw 50 is then rotated so as to be protracted or moved into the slot 20 and to thereby move the ful- Patnted Jan. 20, 1959 Crum block to the right or away from wall 18. As soon as the desired adjustment is attained, rotation of screw 50 is stopped and cotter 59 is then reinserted in the fulcrum block hub and the screw end and the assembly is thus maintained at the desired position.

The key 61 merely serves to prevent the screw body fulcrum block having a pair of spaced side walls inter connected at one end thereof by a h ub, said side walls being spaced from the arms, said side walls having flanges extending outwardly thereof and being engageable with corresponding lateral edges of the frame arms, a pair of L-shaped retaining plates interposed between the side walls and the frame arms, said plates slidably engaging said frame arms, said plates precluding sliding engagement between said side walls and frame arms, said plates having side elements extending outwardly therefrom and engaging opposite lateral edges of the frame arms, said plates 'being rigidly secured to said fulcrum block, a pivotal connection at the end of said assembly remote from said hub for connecting an associatedibrake ele ment to said assembly, and means interconnecting the hub and the adjacent end of the adjuster whereby predetermined movement of the assembly may be affected.

2. In a brake slack adjuster, the combination of: a frame comprising a 'pair of spaced arms interconnected at their ends, said arms defining a longitudinally extending slot, a unitary fulcrum block assembly disposed within said slot, said assembly comprising a pair of plates disposed within said slot, each of said plates having a pair of elements, one of said plate elements being disposed within said slot in complementary sliding engagement with a related frame arm, the other of said plate elements being disposed outside of said slot in interlocking engagement with said related frame arm, a fulcrum block disposed within said slot between said plates and xed thereto, said block comprising a pair of walls interconnected at their ends by a hub, said Walls 'being spaced from said frame arms, said Walls comprising flanges disposed outside of said slot, said anges extending outwardly from said blo-ck in interlocking engagement with said frame arms, means interconnecting the block hub and the related end of the frame for selectively positioning said assembly, and a pivotal connection formed by said block arms and plates, said pivotal connection being defined by aligned slots disposed in said plates 'and block walls and between said frame arms.

3. in a brake slack adjuster, the combination of: a frame comprising a pair of spaced arms, a Wall interconnecting said arms and defining therewith a slot extending longitudinally of said frame, a unitary fulcrum block assembly in said slot and movable lengthwise thereof, said assembly comprising a fulcrum block including a pair of spaced side walls, a hub interconnecting said side walls and dening therewith a lever opening, slots in said side walls extending from their free ends toward said hub, spaced plates disposed between said arms and respective -side walls, said plates spacing the side walls from the arms and having anges overlapping corresponding edges of said arms, said side walls having tlanges overlapping opposite corresponding edges of said arms, slots in said plates extending from the edges thereof remote from their flanges, the inner ends of the slots in the plates and the inner ends of the slots in the side walls being registered, a brake lever fulcrum pin journalled in all of said slots at their inner ends, means connecting the rstmentioned wall to the hub for adjusting the space between the hub and first-mentioned wall, `and means connecting the plates to the side walls for movement therewith longitudinally of the slot.

References Cited in the lle of this patent UNITED STATES PATENTS FOREIGN PATENTS Canada Jan. l, 1952 

